Detection of Glaucoma

Question 1

What are the 5 points of ONH examination?

Answer 1

1.NRR thinning
2.RNFL defect
3.Disc haemorrhage
4. Disc asymmetry
5. PPA - peri-papillary atrophy

Question 2

What are the NRR changes to consider?

Answer 2

-Progressive thinning of NRR – diffuse thinning or localised/focal damage =notching (bites) or focal rim thinning
-ISNT rule not followed= raise suspicion : INFERIOR & SUPERIOR rims are affected first.
-As rims thin- cupping will increase- larger C/D

Question 3

What is the NRR and its properties?

Answer 3

*NRR= tissue between border of cup and border of disc.
-It mainly contains nerve fibres (+ some glial cells) + is normally pink/orange. Tend to be symmetrical sup + inferiorly – ISNT rule.

Question 4

What is the function of the O.disc and NFL?

Answer 4

-RNFL is formed by ganglion cell axons, which collect the visual impulses that begin with the rods + cones (photoreceptors) and pass visual impulses to RNFL–> to optic nerve.

• Optic disc - is the point where axons of RGC come together & represents the beginning of the optic nerve
  -disc carries about 1-1.2million nerve fibres from eye towards brain

Question 5

What patterns occur in RNFL defect?

Answer 5

• Two patterns occur:
  ■ Localised wedge-shaped defects
  ■ Diffuse defects that are larger and have indistinct borders
  ■Walls of peripapillary vessels are underlying choroid are more visible
  ■■ defect looks like loss of striation in retina and darker zones where brightness is usually expected.

Question 6

Describe what the RNFL looks like in a normal eye?

Answer 6

-Usually BRIGHT / WHITE STRIATIONS radiating outwards from Optic disc
-more obvious in Sup temp and Inf temp (RNFL thickest)